1. Field of the Invention
The present invention relates to a steering device including a telescopic adjustment mechanism, the steering device having satisfactory telescopic operability by reducing a harmful effect of shape deformation in weldbonding and improving assembly accuracy.
2. Description of the Related Art
In general, in a steering device including a tilting/telescopic mechanism, a part where components are bonded by welding is present in the structure thereof. For example, in Japanese Patent Application Laid-Open No. 2009-029224, a distance bracket, in which a long hole for telescoping is formed, and an upper jacket are welded. Further, in Japanese Patent Application Laid-Open No. 2008-100597, a bonding support bracket mounted with a second friction plate, in which a telescopic long hole is formed, is welded to an inner column.
Specifically, Japanese Patent Application Laid-Open Nos. 2009-029224 and 2008-100597 are generally explained with parentheses added to the reference numerals and signs used in the respective patent literatures. In Japanese Patent Application Laid-Open No. 2009-029224, a substantially U-shaped distance bracket (4), in which a long hole for telescoping (4d) is formed, is integrally bonded to the lower surface of the lower end portion of an upper jacket (1b) by weldbonding. A pair of side brackets (3c, 3c) is provided to sandwich the distance bracket (4).
In the outward direction of the side bracket (3c), three tilt friction plates (5) and three telescopic friction plates (6) are stacked and disposed to be alternately superimposed in the up-down direction and the vehicle body front-back direction, which are crossing directions. The lower part of the tilt friction plate (6) is inserted over a support pin (3e) formed in the side bracket (3c). On the other hand, the vehicle body front part of the telescopic friction plate (6) is inserted over a support pin (4e) formed in the distance bracket (4).
In Japanese Patent Application Laid-Open No. 2008-100597, a bonding support bracket (48) is welded and fixed to the intermediate part lower surface of an inner column (6a). A pair of bent plate sections (49, 49) bent at a right angle toward the front is formed at the lower half part left and right both end portions of the bonding support bracket (48). A support plate section (50) bent toward the front is formed at the lower end edge of the bonding support bracket (48).
When the lower end portions of second friction plates (40a, 40b) are supported on the intermediate part lower surface of the inner column (6a), in a state in which coupling sections (46a, 46b) that couple the rear end edges of the second friction plates (40a, 40b) are laid one on top of the other, the lower end edges of the coupling sections (46a, 46b) are placed on the upper surface of the support plate section (50). In this state, a holding bracket (51) is pushed into the rear end portion inner sides of the second friction plates (40a, 40b). The holding bracket (51) is fixed to the bonding support bracket (48) by holding screws (52, 52) inserted through both the bent plate sections (49, 49).
In Japanese Patent Application Laid-Open No. 2009-029224, the distance bracket (4) is firmly attached to the upper jacket (1b) by welding. Therefore, it is likely that distortion or deformation occurs in the distance bracket (4) because of thermal effect during welding work. When distortion occurs, parallelism of the long hole for telescoping (4d) is not maintained. Feeling during telescopic adjustment is deteriorated. Further, assemblability of components is deteriorated.
In Japanese Patent Application Laid-Open No. 2008-100597, the bonding support bracket (48) is welded and fixed to the intermediate part lower surface of the inner column (6a). Therefore, as in Japanese Patent Application Laid-Open No. 2009-029224, it is likely that distortion or deformation occurs because of thermal effect during welding work. When distortion occurs, parallelism of the bent plate section (49) is not maintained. Assembly accuracy of the second friction plates (40a, 40b) bonded to the bent plate section (49) is deteriorated.
In the second friction plates (40a, 40b), second long holes (28, 28), which are long holes for telescoping, are formed. Therefore, it is likely that feeling during telescopic adjustment is deteriorated. The bonding support bracket (48) is a bracket for fixing the second friction plates (40a, 40b) and is a dedicated component not particularly including other functions. Therefore, the number of components increases.